height map brings weird result
This occurs because of two things:


Your image is a highly compressed JPG, creating banding issues and artifacts which get amplified by using it as a bump map.
I would suggest using a PNG with a higher bitrate.
You set the bump strength to 3, which makes the color data clip. 0-1 is the safe margin if you have 100% black in your image (which you do). I suggest working with the distance value instead if you want to have a more pronounced depth effect.